<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>


    <meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>Using Ajax for deferred loading of items</title>

<style type="text/css">
/*margin and padding on body element
  can introduce errors in determining
  element position and are not recommended;
  we turn them off as a foundation for YUI
  CSS treatments. */
body {
	margin:0;
	padding:0;
}
</style>

<link rel="stylesheet" type="text/css" href="../../build/fonts/fonts-min.css" />
<link rel="stylesheet" type="text/css" href="../../build/carousel/assets/skins/sam/carousel.css" />
<script type="text/javascript" src="../../build/yahoo-dom-event/yahoo-dom-event.js"></script>
<script type="text/javascript" src="../../build/connection/connection-min.js"></script>
<script type="text/javascript" src="../../build/element/element-min.js"></script>
<script type="text/javascript" src="../../build/carousel/carousel-min.js"></script>


<!--begin custom header content for this example-->
<style type="text/css">
    /* Style the spotlight container */
    #spotlight {
        border: 1px solid #ccc;
        height: 240px;
        margin: 10px auto;
        padding: 1px;
        text-align: center;
        width: 240px;
    }

    #carousel {
        margin: 0;
    }

    #container {
        margin: 0 auto;
    }

    .yui-skin-sam .yui-carousel-nav ul,
    .yui-skin-sam .yui-carousel-nav select {
        display: none;
    }
    /* Always be sure to give your carousel items a width and a height */
    .yui-carousel-element li {
        height: 75px;
        width: 75px;
    }
</style>

<!--end custom header content for this example-->

</head>

<body class="yui-skin-sam">


<h1>Using Ajax for deferred loading of items</h1>

<div class="exampleIntro">
	<p>
    This example showcases the dynamic loading capabilities of the <a href="http://developer.yahoo.com/yui/carousel/">YUI Carousel Control</a>.  The YUI Carousel Control exposes an event called <code>loadItems</code>.  This
    event is fired whenever the Carousel needs items to be loaded into it for
    display.  Subscribing  to this event makes it easy to dynamically load
    the next set of images.
</p>
			
</div>

<!--BEGIN SOURCE CODE FOR EXAMPLE =============================== -->

<!-- The Carousel container -->
<div id="container">
    <ol id="carousel"></ol>
</div>
<!-- The spotlight container -->
<div id="spotlight"></div>
<script>
    var curpos, items = [];

    function getImageTag(img) {
        return "<img src=\"" + img + "\" height=\"75\" width=\"75\">";
    }

    function getImages() {
        var carousel = this;
                
        YAHOO.util.Connect.asyncRequest("GET", "assets/php/getimages.php?pos="+curpos,
                {
                    success: function (o) {
                        var i = curpos,
                            j = 0,
                            r = eval('(' + o.responseText + ')');
                            
                        curpos += r.length;

                        while (i < curpos) {
                            if (r[j]) {
                                carousel.addItem(getImageTag(r[j]));
                            } else {
                                break;
                            }
                            i++;
                            j++;
                        }

                        carousel.set("selectedItem", carousel.get("firstVisible"));
                    },

                    failure: function (o) {
                        alert("Ajax request failed!");
                    }
        });
    }
                
    // Get the image link from within its (parent) container.
    function getLargeImage(parent) {
        var el = parent.firstChild;
                
        while (el) { // walk through till as long as there's an element
            if (el.nodeName.toUpperCase() == "IMG") { // found an image
                // flickr uses "_s" suffix for small, and "_m" for big
                // images respectively
                return el.src.replace(/_s\.jpg$/, "_m.jpg");
            }
            el = el.nextSibling;
        }
                
        return "";
    }

    YAHOO.util.Event.onDOMReady(function (ev) {
        var carousel, spotlight = YAHOO.util.Dom.get("spotlight");

        carousel = new YAHOO.widget.Carousel("container", {

             /* Setting numItems is required for dynamic loading. This property lets Carousel 
                know how many total items it will ever be populated with (statically and/or dynamically).
                Not to be confused with numVisible: the number of items shown to a 
                user per page. In this example, we don't specify numVisible and Carousel 
                defaults to 3 items visible per page. */
                 
                numItems: 17
        });
	
        YAHOO.util.Connect.asyncRequest("GET", "assets/php/getimages.php", {
                success: function (o) {
                    var i, r = eval('(' + o.responseText + ')');
                    
                    curpos = r.length;

                    for (i = 0; i < curpos; i++) {
                        items.push(r[i]);
                    }

                    // check if the Carousel widget is available
                    if (typeof carousel != "undefined") {
                        for (i = 0; i < curpos; i++) {
                            // if so, shove the elements into it
                            carousel.addItem(getImageTag(items[i]));
                        }
                        carousel.set("selectedItem", 0);
                        items = [];
                    }
                },

                failure: function (o) {
                    alert("Ajax request failed!");
                }
        });
                
        carousel.on("loadItems", function (o) {
            // more items available?
            getImages.call(this);
        });
                
        carousel.on("itemSelected", function (index) {
            // item has the reference to the Carousel's item
            var item = carousel.getElementForItem(index);

            if (item) {
                spotlight.innerHTML = "<img src=\""+getLargeImage(item)+"\">";
            }
        });
            
        carousel.render();
        carousel.show();
    });

</script>

<!--END SOURCE CODE FOR EXAMPLE =============================== -->

</body>
</html>
